遊戲有三個介面，分別是開始介面，遊戲介面和遊戲結束介面。
遊戲的大背景
上下移動的遊戲標題和翅膀擺動的小鳥
#start 按鈕，點擊進入遊戲介面
一直移動的地面
<!DOCTYPE html><html><head><meta charset="utf-8" /><title>Fly Bird</title><link rel="stylesheet" type="text/css" href="css/index.css?1.1.11"/></head><body><div id="wrapBg"> <!--游戏背景--><div id="headTitle"> <!--开始标题--><img id="headBird" src="img/bird0.png" alt="小鸟" /> <!--标题中的小鸟--></div><button id="startBtn" ></button> <!--开始按钮--><div id="grassLand1"></div> <!--草地1--><div id="grassLand2"></div> <!--草地2--></div></body></html>
#wrapBg{/*游戏背景*/width: 343px;height: 480px; margin: 0 auto;background-image:url(../img/bg.jpg);position: relative;top: 100px;overflow: hidden;
}#headTitle{/*开始标题*/width: 236px;height: 77px;background-image: url(../img/head.jpg);position: absolute; left: 53px; top: 100px;
}#headBird{/*开始标题中的小鸟*/float:right;margin-top: 25px;
}#startBtn{/*开始按钮*/width: 85px;height: 29px;padding: 0;margin: 0;background-image: url(../img/start.jpg);position: absolute;left: 129px;top: 250px;
}#grassLand1{/*草地1*/height: 14px;width: 343px;background-image: url(../img/banner.jpg);position: absolute;top: 423px;
}#grassLand2{/*草地2*/height: 14px;width: 343px;background-image: url(../img/banner.jpg);position: absolute;top: 423px;left: 343px;
}
逐幀動畫是一種常見的動畫形式（Frame By Frame），其原理是在「連續的關鍵影格」中分解動畫動作，也就是在時間軸的每個畫面上逐格繪製不同的內容，使其連續播放而成動畫。
var jsHeadTitle = document.getElementById("headTitle");// 获取标题var jsHeadBird = document.getElementById("headBird"); // 获取标题中小鸟var Y = 3;//标题的摆动幅度var index = 0;var imgArr = ["img/bird0.png","img/bird1.png"] //将小鸟图片路径放入一个数组，利用逐帧动画的原理做出小鸟翅膀摆动的样子var headWaveTimer = setInterval(headWave,200); //设置标题上下摆动的定时器function headWave() {
Y *= -1;
jsHeadTitle.style.top = jsHeadTitle.offsetTop + Y + "px";
jsHeadBird.src = imgArr[index++];if (index == 2) {
index = 0;
}
} var jsGrassLand1 = document.getElementById("grassLand1"); //获取草地1
var jsGrassLand2 = document.getElementById("grassLand2"); //获取草地2
var landTimer = setInterval(landRun,30); //让草地动起来的定时器
function landRun() {
if (jsGrassLand1.offsetLeft <= -343) {jsGrassLand1.style.left = "343px";
}
if (jsGrassLand2.offsetLeft <= -343) {jsGrassLand2.style.left = "343px";
}jsGrassLand1.style.left = jsGrassLand1.offsetLeft - 3 + "px";jsGrassLand2.style.left = jsGrassLand2.offsetLeft - 3 + "px";
} var jsStartBtn = document.getElementById("startBtn");
jsStartBtn.onclick = function() { //为start按键添加点击事件处理程序
jsHeadTitle.style.display = "none"; //隐藏标题
clearInterval(headWaveTimer); //关闭让标题摆动的定时器
jsStartBtn.style.display = "none"; //隐藏按键//待添加功能//点击开始按键进入游戏界面
}start01.gif
var bird = {flyTimer:null,//小鸟飞翔定时器
wingTimer:null,//小鸟翅膀摆动定时器
div:document.createElement("div"),showBird:function(parentObj) {this.div.style.width = "40px";this.div.style.height = "28px";this.div.style.backgroundImage = "url(img/bird0.png)";this.div.style.backgroundRepeat = "no-repeat";this.div.style.position = "absolute";this.div.style.left = "50px";this.div.style.top = "200px";this.div.style.zIndex = "1";
parentObj.appendChild(this.div); //将小鸟DIV插入游戏界面中
},fallSpeed: 0, //小鸟下落速度
flyBird: function(){ //控制小鸟飞翔下落的函数
bird.flyTimer = setInterval(fly,40);function fly() {
bird.div.style.top = bird.div.offsetTop + bird.fallSpeed++ + "px";if (bird.div.offsetTop < 0) {
bird.fallSpeed = 2; //这里用于控制小鸟不要飞出界面
}if (bird.div.offsetTop >= 395) {
bird.fallSpeed = 0;
clearInterval(bird.flyTimer); //一旦飞到地面，清除定时器
clearInterval(bird.wingTimer); //清除翅膀摆动定时器
}if (bird.fallSpeed > 12) {
bird.fallSpeed = 12; //鸟的最大下落速度控制在12
}
}
},wingWave: function() { //控制小鸟煽动翅膀的函数var up = ["url(img/up_bird0.png)", "url(img/up_bird1.png)"];var down = ["url(img/down_bird0.png)", "url(img/down_bird1.png)"];var i = 0, j = 0;
bird.wingTimer = setInterval(wing,120);//逐帧动画，小鸟煽动翅膀function wing() {if (bird.fallSpeed > 0) {
bird.div.style.backgroundImage = down[i++];if (i==2) {i = 0}
}if (bird.fallSpeed < 0) {
bird.div.style.backgroundImage = up[j++];if (j==2) {j = 0}
}
}
},
};jsStartBtn.onclick = function() { //为start按键添加点击事件处理程序
jsHeadTitle.style.display = "none"; //隐藏标题
clearInterval(headWaveTimer); //关闭让标题摆动的定时器
jsStartBtn.style.display = "none"; //隐藏按键
bird.showBird(jsWrapBg); //插入小鸟到界面中
bird.flyBird(); //控制小鸟飞翔下落
bird.wingWave(); //逐帧动画，小鸟煽动翅膀
jsWrapBg.onclick = function(){
bird.fallSpeed = -8;
};//待添加功能//点击开始按键进入游戏界面
}新增小鳥後的效果
3.2障礙（上管道和下管道）
block示意圖.png障礙分為上管道和下管道，如示意圖所示結構嵌套，這樣就可以透過隨機設定DownDiv2的高度和gapHeight的高度，來改變生成障礙的形態block.js
function Block() {this.upDivWrap = null;this.downDivWrap = null;this.downHeight = baseObj.randomNum(0,150);//随机生成0-150之间的数，用于控制下管道的高度this.gapHeight = baseObj.randomNum(150,160);// 管道中间间隙宽度，通过调节大小，可以的控制游戏难度this.upHeight = 312 - this.downHeight - this.gapHeight;// 用来生成Div的方法this.createDiv = function(url, height, positionType, left, top) {var newDiv = document.createElement("div");
newDiv.style.width = "62px";
newDiv.style.height = height;
newDiv.style.position = positionType;
newDiv.style.left = left;
newDiv.style.top = top;
newDiv.style.backgroundImage = url; //"url(/img/0.jpg)"return newDiv;
};this.createBlock = function() {var upDiv1 = this.createDiv("url(img/up_mod.png)", this.upHeight + "px");var upDiv2 = this.createDiv("url(img/up_pipe.png)", "60px");this.upDivWrap = this.createDiv(null, null, "absolute", "450px");this.upDivWrap.appendChild(upDiv1);this.upDivWrap.appendChild(upDiv2);//生成上方管道var downDiv1 = this.createDiv("url(img/down_pipe.png)", "60px");var downDiv2 = this.createDiv("url(img/down_mod.png)", this.downHeight +"px");this.downDivWrap = this.createDiv(null, null, "absolute", "450px", 363 - this.downHeight + "px");this.downDivWrap.appendChild(downDiv1);this.downDivWrap.appendChild(downDiv2); //生成下方的管道
jsWrapBg.appendChild(this.upDivWrap);
jsWrapBg.appendChild(this.downDivWrap);
};this.moveBlock = function() { //控制管道移动的方法this.upDivWrap.style.left = this.upDivWrap.offsetLeft - 3 + "px";this.downDivWrap.style.left = this.downDivWrap.offsetLeft - 3 + "px";
};
}
var baseObj = {//随机数
randomNum: function(min, max) {return parseInt(Math.random() * (max - min + 1) + min);
},//两个矩形元素之间的碰撞检测
rectangleCrashExamine: function (obj1, obj2) {var obj1Left = obj1.offsetLeft;var obj1Width = obj1.offsetLeft + obj1.offsetWidth;var obj1Top = obj1.offsetTop;var obj1Height = obj1.offsetTop + obj1.offsetHeight;var obj2Left = obj2.offsetLeft;var obj2Width = obj2.offsetLeft + obj2.offsetWidth;var obj2Top = obj2.offsetTop;var obj2Height = obj2.offsetTop + obj2.offsetHeight;if (!(obj1Left > obj2Width || obj1Width < obj2Left || obj1Top > obj2Height || obj1Height < obj2Top)) {return true;
}return false;
},
}; var blocksArr = [];
var blockDistance = baseObj.randomNum(130,250);
var landTimer = setInterval(landRun,30); //让草地动起来的定时器
function landRun() {
if (jsGrassLand1.offsetLeft <= -343) {jsGrassLand1.style.left = "343px";
}
if (jsGrassLand2.offsetLeft <= -343) {jsGrassLand2.style.left = "343px";
}jsGrassLand1.style.left = jsGrassLand1.offsetLeft - 3 + "px";jsGrassLand2.style.left = jsGrassLand2.offsetLeft - 3 + "px";
if (blocksArr.length) {
for (var i = 0; i < blocksArr.length; i++) {blocksArr[i].moveBlock();
var x =baseObj.rectangleCrashExamine(blocksArr[i].downDivWrap, bird.div);
var y = baseObj.rectangleCrashExamine(blocksArr[i].upDivWrap, bird.div);
var z = bird.div.offsetTop >= 390;
if (x || y || z) {
window.clearInterval(landTimer);//清除landTimer定时器bird.fallSpeed = 0; //小鸟下落jsWrapBg.onclick = null; //消除点击事件
}
}
if (blocksArr[blocksArr.length - 1].downDivWrap.offsetLeft < (450 - blockDistance)) {blockDistance = baseObj.randomNum(130,250);
var newBlock = new Block();
newBlock.createBlock();blocksArr.push(newBlock);
}
if (blocksArr[0].downDivWrap.offsetLeft < -50) {jsWrapBg.removeChild(blocksArr[0].downDivWrap);jsWrapBg.removeChild(blocksArr[0].upDivWrap);blocksArr.shift(blocksArr[0]);
}
}
}游戏中的计分器相对较好实现，我们就实现最大为三位数的计分器吧。
html
<div id="score">
<div id="num1"></div>
<div id="num2"></div>
<div id="num3"></div>
</div>css样式
#score{position:absolute;left: 130px;top:50px;z-index: 1;
}#score div{height: 39px;width: 28px;float: left;background-image: url(../img/0.jpg);display: none;
}js
var jsScore = document.getElementById("score");
var jsNum1 = document.getElementById("num1");
var jsNum2 = document.getElementById("num2");
var jsNum3 = document.getElementById("num3");
var score = 0;实现计数器功能，最重要的是如何判断走过水管的数量，我们以水管的位置来判断。bird的定位left为50px，水管的宽度是62px，当水管越过小鸟的时候，水管距离它父级的定位offsetLeft 是 -12px。每当有一个水管到达此位置，score++；
在start按钮的事件处理程序中加入
jsNum1.style.display = "block";// 在点击开始之后，让计数器显示出来。
if (blocksArr[0].downDivWrap.offsetLeft == -12) {score++;//积分面板
if (score < 10) {jsNum1.style.backgroundImage = "url(img/" + score + ".jpg)";
} else if (score < 100) {jsNum2.style.display = "block";jsNum1.style.backgroundImage = "url(img/" + parseInt(score/10) + ".jpg)";jsNum2.style.backgroundImage = "url(img/" + score%10 + ".jpg)";
} else if (score < 1000) {jsNum3.style.display = "block";jsNum1.style.backgroundImage = "url(img/" + parseInt(score/100) + ".jpg)";jsNum2.style.backgroundImage = "url(img/" + parseInt(score/10)%10 + ".jpg)";jsNum3.style.backgroundImage = "url(img/" + score%10 + ".jpg)";
}
console.log(score);
}目前效果 ，计数器功能完成。
当小鸟和管道碰撞或者和地面碰撞时候，隐藏计分器，弹出结束面板。
结束界面主要有“结束面板”和“ok”按钮，这里需要为“ok”按钮添加点击事件。
<div id="gameOver">
<img src="img/game_over.jpg" alt="game over" />
<img src="img/message.jpg" alt="message" />
<img id="ok" src="img/ok.jpg" alt="ok" />
</div>#gameOver{position: absolute;top: 100px;text-align: center;display: none;z-index: 1;
}为“OK”按钮添加事件
jsOkBtn.onclick = function() {window.location.href = "index.html"; //刷新页面
}最终效果
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